Effect of the interval between irradiation and conception on mutation frequency in female mice.

Abstract

Irradiation of female mice with fission neutrons showed that the interval between irradiation and conception has a striking effect on the mutation frequency seen in the offspring. In the 1st 7 weeks after irradiation with approximately 63 rads, the mutation frequency is high. A total of 59 specific locus mutations was observed in 89,301 offspring conceived in that period. After that, no mutations were found in a total of 120,483 offspring. There is some evidence for a similar effect with gamma irradiation. It is not yet known whether the result is due to a low mutational sensitivity of oOcytes in immature follicle stages, to an efficient repair mechanism in these stages, or to cell selection. It is not safe to assume that the results will apply to the human female, but this is a possibility that should be considered in evaluating human data and in estimating the genetic hazards of radiation.